High-power transmission line switch



y 1951 I R. A. KENT 2,561,871

HIGH-POWER TRANSMISSION LINE SWITCH Filed larch 22 1947 In \Zkq 'Q 3 Sheets-$heet 1 -INS 'nrramvir R. A. KENT HIGH-POWER 'I'RANSJISSION LINE SWITCH July 24, 1951 3 Sheets-Sheet 3 Filed larch 22, 1947 Patented July 24, 1951 men-rowan TRANSMISSION LINE swrron Ralph A. Kent, New York, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application March 22, 1947, Serial No. 736,454

4 Claims.

This invention relates to a new and useful transmission line switch for balanced circuits, which switch will connect a transmitter to or disconnect it from one or mor transmitters or transmission lines.

An object of this invention is to connect high power medium frequency, highfrequency, or ultra high frequency energy to a balanced or an unbalanced transmission line without discontinuity, or change of impedance.

Another object of this invention is to eliminate the use of stubs, etc, in the switching combination, commonly used with switches of the prior art.

A feature of the switching systemof this invention is that the fixed contacts of the conductors of the diiierent transmission lines are arranged on a circular arc in front of which passes a carriage type of switching device to selectively contact conductors which are connected to the transmitter. The electrical contacts between the carriage and the fixed contact positions ar composed of resilient multi-point contacts. The carriage carries the feed lines with the power. The power source is connected to the feed line which pivots at the center of the arc.

This invention will best be understood by referring to the accompanying drawings, in which:

Fig. l is a plan view of the switch of this invention;

Fig. 2 is a sectional elevation, looking from a position indicated by the lines 2-2;

Fig. 3 is a side elevation of Fig. 1, partly in section, the section being taken on line 3-3 of Fig.1;

Fig. 4 is a sectional elevation taken on the line 4-4 of Fig. 3;

Fig. 5 is a schematic diagram showing the conductor structural supports which are arranged in a neutral plane of the electric field of the high frequency conductors;

Fig. 6 is a circuit diagram showing a switching arrangement using two switches of the type described in this invention; and

Fig. 7 is a diagram of another switching arrangement using three switches of this invention.

Referring now in detail to Figs. 1 to 4 of the drawings, there are two upright metallic posts 2 and 3 arranged upon a support base I which may be a casting, sheet steel, or the floor of a building. The posts are preferably in the form of a channel iron. Each post is provided with a foot member 2A. An insulating panel 4 is fastened to the 'channel irons 2 and 3. In the central portion of therefrom, there is located a vertical panel 32 around the pivot 6 of bracket 5. The base of bracket! is provided with two bosses 8 and 9 into which is secured two support rods or tubes or pipes l0 and II. The rods Ill and II terminate in flanged support members l2 and I3 which are secured to an upright insulating panel M. An insulating shelf member I 5 is secured to the central portion of panel I4 by any suitable means. Located at the far end of shelf l5 there is secured a motor I6 and a gear reduction unit ll. A roller i8 is secured to the shaft of the gear reduction unit I I. At the end opposite the motor and gear reduction unit" there is located a. bearing [9 in which a shaft 20 and a roller 2| operate. The motor l6 may be placed away from the switching assembly itself and the switch arm activated by means of pulling wires, chains, or any similar arrangement; or it may be operated manually. There are three fixed shelf portions 22, 23 and 24 located in a horizontal line with shelf [5. The curved face of each shelf 22, 23 and has a radius slightly greater than that of the radius of shelf l5 to prevent binding. Shelf portions 22, .23 and 24 are secured by any suitable means to the vertical insulating panels 25, 26 and 2'! respectively, the panels being supported from base I by four channel shaped posts 28, 29, 30 and 3|. In line with panels 25, 26 and 21, but spaced apart also of insulation material, which panel is supported by two upright posts 33 and 34. In the same plane as pivot 6 but spaced apart therefrom, there are located on panel 4 four semispherical hollow insulatin members 35, 36, 31 and '38, or any other suitable insulators. Also located on the central portion of panel [4 there are four semi-spherical hollow insulators (or any other suitable insulators) 39, 40, 4| and 42, the spacing being in line with the spacing of the hollow insulators located on panel 4. Similar insulators (43 to 54, inclusive) ar located on panels 22, 23 and 24. There are twelve insulators to 66, inclusive-insulators 58 and 66 not shown in the drawing are the rearmost counterparts of insulators 56 and 64 respectively) located on panel 32.

The insulators 35 and 35, which are mounted in the upper portion of panel 4, are provided with a threaded conducting rod 10, one end of which is threaded at ll with suitable nuts and washers for making connection to a radio transmitter 89. The insulators 31 and 38, located on the lower portion of panel 4, are provided with a similar rod 12 which is also threaded for receiving washers and nuts which make connection to the other terminal of the transmitter. Rods II and I! are provided with connection means Ila and 14 for making connection to flexible conductors II and IS. The connection points 11a and 14 are located soastobeinlinewiththepivotl. Insulators 39 and ll, which are located in the upper portion of panel M, are provided with a connection rod I1, one end being provided with connection means I! for connecting to the conductor II. The other end of rod 11 is provided with a resilient spring contact member ll constructed of a plurality of flexible metallic springs having sufficient resiliency and current ca y g capacity for making connection to the desired transmitting circuit. Insulators ll and 42 are provided with a rod ll of similar construction and serving a similar purpose to that of rod II.

Each pair of insulators ll to N, inclusive, is provided with a fixed contact rod II, having a fixed contact member I: at one end thereof, the other end being provided with a connection member II. The contacts I! are positioned on the rod so as to make electrical connection with the flexible contact ll. Each pair of insulators 55 to 66, inclusive, is provided with a connection rod l5, one end of which is arranged to make connection to a conductor 86 and the other end being provided with suitable washers and nuts for making connection either to the transmission lines or to the antenna.

Although the switch of this invention has been described as having three panels for a three position switch, positions may be added as indicated by the broken lines. The number of possible positions is only limited by the switch radius. The panel 32 between posts 33 and 34 can be substituted for the wall of a building, a wall between two rooms, or a similar arrangement.

In the operation of this device, the transmission lines from a radio transmitter or group of transmitters is connected by suitable transmis sion lines equally spaced to connection points or input terminals Ii and 13, for switching the transmitter to the transmission lines and/or outgoing antennas at a connection point II. It is possible to place the pivoted moving mechanical part of the switch with the driving mechanism (including motor i6, gear reduction unit I1, and roller ll) in position for selecting either one of the contacts or output terminals it for making electrical connection to the transmission lines at point 85 by remote control. The rotation of the movable switch arm (which is pivoted at 6) is accomplished by having rollers l8 and 2| roll upon a fixed support path on panels 22, 23 and 24. With this switching arrangement, the conductors l and I6 are arranged at equally spaced distances or in a neutral plane with the electrical field which exists between the two conductors of a balanced transmission line, the conductors "and It being indicated in Fig. 5. In other words the conductors are located on a straight line and equally spaced between the metallic supports and also midway between the movable arm, which arm may be connected to ground or a point of given reference potential. The metal parts (which include brackets 5 and I and support rods II and H) can be connected to ground, indicated at 90. With this symmetrical arrangement of the conductors l5 and It with respect to the grounded metal parts of the movable arm there will not be any irregularities or discontinuities into the system which is connected with the switching mechanism. The physical spacing. wire diameter, etc. of the energy carrying line from the source of power through the switching appliance of this invention to and including the transmission line proper can, because of the structural arrangement of placing the conductors It and 18 in the neutral plane, insure continuity and uniformity of characteristic impedance of the line as it passes through the switch. This arrangement will eliminate terminal stubs or dead-end line sections, which were inherent in most prior art switching appliances.

Referring to Fig. 6 of the drawing, a single wire circuit diagram is shown. For simplicity, the arms 04 and I! are each double-pole, as indicated by conductors I5 and 16. Also, contacts II and 81 are double layer contacts, to be used if it is required to connect more load trans mission lines to the feeder lines than it is possible to arrange in one circular arc (with a straight line path). This can be accomplished by providing two switching arrangements, which include a pair of movable switch arms II and 95, the arms being arranged to move the carriage to cover another row of contacts indicated by the circular arcs 96, 91. With this arrangement it is possible to position the above mentioned switches 94 and 95 in series. In addition, double throw switches of any conventional design suitable for high frequency switching, attached to the transmission lines, can connect the different transmission lines to any two rows of contacts of any power source.

Fig. 7 shows the use of three double pole switches with double layer of contacts, in the same way as shown in Fig. 6. Thus, double layer switches can connect one source of power to different switch appliances; or two different sources of power alternately to one switching appliance. These additional switching systems of double throw switches may be operated either separately or simultaneously.

The above description covers one or more sources of power to be connected to a multiple of transmission lines. By reversing the direction of power flow, multiple sources of power can be connected to one or more transmission lines.

What is claimed is:

1. A high frequency transmission line switching arrangement comprising a pair of input terminals. a plurality of pairs of output terminals for selective. association with said input terminals, the lines interconnecting the terminals of each of said pairs of terminals being parallel, said pairs of output terminals being arranged equidistantly from a central line parallel to said interconnecting lines and located between said input and output terminals, a movable switch arm of conductive material pivotally arranged ior rotation only about said central line, said switch arm having two spaced conductors constituting a transmission line electrically coupled at one end thereof to said input terminals and at the other end thereof provided with slidable contacts to engage a single pair of said ouput terminals in any one operative position of said arm, said switch arm being grounded and positioned midway between said two spaced conductors and in the neutral plane between said spaced conductors.

2. A high frequency transmission line switching arrangement comprising a pair of input terminals, a plurality of pairs of output terminals for selective association with said input terminals. the lines interconnecting the terminals of each of said pairs ofterminals being parallel, aid pairs of output terminals being arranged equidistantly from a line parallel to said interconnecting lines and located between said input and output terminals, a movable switch arm of conductive material pivotally arranged on said line for rotation only about that line, means to rotate laid movable arm including an electric motor which is secured to a portion of said movable arm, laid switch arm having two spaced conductors constituting a transmission line electrically coupled at one end thereof to said input terminals and at the other end thereof provided with slidable contacts to engage a single pair of said output terminals in any one operative position of laid arm, said switch arm being grounded and positioned midway between said two spaced conductors and parallel thereto in the neutral plane between said spaced conductors. r

3. A high frequency transmission line switchlng arrangement comprising a pair of input terminals, a plurality of pairs of output terminals for selective association with said input terminals, the lines interconnecting the terminals 01' each of said pairs of terminals being parallel, said pairs of output terminals being arrangedequidistantly from a central line parallel to said interconnecting lines and located between said input and output terminals, a movable switch arm of conductive material pivotally arranged for rotation only about said central line, means coupled to said movable arm including an electric motor to remotely control the movement of said switch arm, said switch arm having two spaced conductors constituting a transmission line electrically coupled at one end thereof to said input terminals and at the other end thereof provided'with slidable contacts to engage a single pair of said output terminals in any one operative position of said .arm, said switch arm being grounded and positioned midway between said two spaced conductors and parallel thereto in the neutral plane between said spaced conductors.

minals and 4. A high frequency transmission line switching arrangement comprising a metallic supporting structure, a pair of input terminals insulatingly arranged on said supporting structure, a

plurality of pairs of output terminals for alternative association with said input terminals insulatingly arranged on said supporting structure, the lines interconnecting the terminals of each of said pairs of terminals being parallel, said pairs of output terminals being arranged equidistantly from a central line parallel to said interconnecting lines and located between said input and output terminals, a movable switch arm of conductive material pivotally arranged for rotation only about said central line and secured to said supporting structure, said switch arm having two spaced conductors constituting a transmission line insulatingly arranged thereon and electrically coupled at one end thereof to said input terat the other end thereof provided with slidable contacts to engage a single pair of said output terminals in any one operative position of said arm, said switch arm being grounded and positioned midway between said two spaced conductors and in the neutral plane between said conductors.

RALPH A. KENT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

